SOURCE

let a = [1,3,4,5,6,7]
 
console.log(Array.isArray(a)) //true
console.log(Array.isArray([]))


let b = [1,4,5]
console.log(b instanceof Array)

//利用构造函数
function isArray(arr) {
    return arr.constructor.toString().indexOf("Array") > -1;
}


function isArray(arr) {
    return arr.constructor === Array;
} 
console.log(isArray(a)) 

let o = {}
console.log(o.constructor === Object)  // true

let m = new Object
console.log(m.constructor === Object) // true

let p = []
console.log(p.constructor === Array) // true

let e = new Array
console.log(e.constructor === Array) // true

let n = new Number(3)
console.log(n.constructor === Number) // true

let str = 3
const arr = new Array(str)
console.log(arr.constructor === Array)
console.log('arr.constructor is ' + arr.constructor)
console.log(arr.constructor.toString())
console.log(typeof function(){})